Remote control of an HVAC system that uses a common temperature setpoint for both heat and cool modes

Abstract

An HVAC system includes an HVAC unit having a cooling mode and a heating mode for conditioning the air in an inside space, and a programmable thermostat located remotely from the HVAC unit. The HVAC unit may have an onboard controller configured to control when the HVAC unit is in the cooling mode or heating mode, and whether the HVAC unit is activated or not. In some cases, the onboard controller of the HVAC unit may use a common temperature setpoint when controlling in the cooling mode and the heating mode. The programmable thermostat may have a programmable schedule with a plurality of time periods, where each time period has a heating setpoint and a cooling setpoint separated by a dead band. The onboard controller of the HVAC unit may be configured to accept input signals from the remotely located thermostat. The remotely located thermostat may send one or more input signals to the onboard controller of the HVAC unit in accordance with the programmable schedule, where the one or more input signals cause the onboard controller of the HVAC unit to set the HVAC unit to a particular one of the cooling mode and the heating mode, and to activate the HVAC unit so as to condition the air in the inside space in the particular one of the cooling mode and the heating mode.

What is claimed is: 
     
       1. A method for controlling a mini-split system HVAC unit via a thermostat that is located remotely from the HVAC unit, the HVAC unit having a cooling mode and a heating mode for conditioning air in the inside space, the HVAC unit having a temperature sensor for providing a locally sensed air temperature and an onboard controller that is configured to activate and deactivate the HVAC unit so as to conditioning the air in the inside space in accordance with a control setpoint of the onboard controller, the onboard controller of the HVAC unit is further configured to accept input signals wirelessly transmitted from the remotely located thermostat, the method comprising:
 the remotely located thermostat comparing a sensed temperature in the inside space with a setpoint, and determining if the sensed temperature is different from the setpoint by at least a predetermined amount; and 
 if the sensed temperature is different from the setpoint by at least the predetermined amount, the thermostat wirelessly sending one or more input signals to the onboard controller of the HVAC unit, the one or more input signals instructing the onboard controller of the HVAC unit to set the HVAC unit to a particular one of the cooling mode and the heating mode, and to set the control setpoint of the onboard controller to a value that will cause the onboard controller to activate the HVAC unit in the particular one of the cooling mode and the heating mode. 
 
     
     
       2. The method of  claim 1 , wherein the one or more input signals cause the onboard controller of the HVAC unit to override the cooling mode and the heating mode that the onboard controller would otherwise set. 
     
     
       3. The method of  claim 1 , wherein the thermostat communicates a measure related to the air temperature in the inside space to the onboard controller of the HVAC system, wherein the onboard controller controls the measure related to the air temperature in the inside space to the control setpoint while the HVAC system is in the particular one of the cooling mode and the heating mode. 
     
     
       4. The method of  claim 1 , wherein after the HVAC unit is activated, and if the sensed temperature in the inside space becomes not different from the setpoint by at least the predetermined amount, the thermostat sends one or more input signals to the onboard controller of the HVAC unit that cause the onboard controller to deactivate the HVAC unit. 
     
     
       5. The method of  claim 1 , wherein the thermostat wirelessly communicates the control setpoint to the onboard controller of the HVAC system, wherein the onboard controller controls to the control setpoint while the HVAC system is in the particular one of the cooling mode and the heating mode. 
     
     
       6. The method of  claim 5 , wherein the control setpoint is an artificial control setpoint that is outside an expected temperature range of sensed temperature values in order to cause the onboard controller of the HVAC unit to activate the HVAC unit so as to condition the air in the inside space in the particular one of the cooling mode and the heating mode. 
     
     
       7. The method of  claim 1 , further comprising maintaining in a memory of the thermostat a schedule having a plurality of time periods, each time period having one or more time period setpoints, wherein, in the comparing step, the sensed temperature in the inside space is compared with a corresponding one of the one or more time period setpoints of the schedule. 
     
     
       8. The method of  claim 7 , wherein at least one of the plurality of time periods includes a heating setpoint and a cooling setpoint, wherein the thermostat is configured to select between the heating setpoint and the cooling setpoint for the at least one time period for use in the comparing step when in an auto changeover mode. 
     
     
       9. The method of  claim 8 , wherein:
 if the sensed temperature in the inside space is higher than the cooling setpoint, the thermostat wirelessly sends one or more input signals that cause the onboard controller of the HVAC unit to set the HVAC unit to the cooling mode and activate the HVAC unit; and 
 if the sensed temperature in the inside space is lower than the heating setpoint, the thermostat wirelessly sends one or more input signals that cause the onboard controller of the HVAC unit to set the HVAC unit to the heating mode and activate the HVAC unit. 
 
     
     
       10. A method for controlling a mini-split system HVAC unit via a thermostat that is located remotely from the HVAC unit, the HVAC unit having a cooling mode and a heating mode for conditioning air in the inside space, the HVAC unit having a control setpoint, temperature sensor and an onboard controller that is configured to control whether the HVAC unit is in the cooling mode or heating mode in accordance with a comparison between the control setpoint and a local temperature indicated by the temperature sensor, and whether the HVAC unit is activated or not, the onboard controller of the HVAC unit is configured to accept input signals wirelessly transmitted from the remotely located thermostat, the method comprising:
 receiving one or more wireless input signals from the thermostat to activate the HVAC unit, wherein the one or more wireless input signals specify either a cooling mode command or a heating mode command; 
 if a cooling mode command is specified by the one or more wireless input signals, forcing the HVAC unit into the cooling mode regardless of the mode otherwise determined by the onboard controller of the HVAC unit; 
 if a heating mode command is specified by the one or more wireless input signals, forcing the HVAC unit into the heating mode regardless of the mode otherwise determined by the onboard controller of the HVAC unit; and 
 with the mode of the HVAC unit set, running the HVAC unit so as to condition the air in the inside space in the set mode. 
 
     
     
       11. The method of  claim 10 , wherein the one or more wireless input signals specify a cooling mode command when a temperature sensed by the thermostat is higher than a temperature set point by a threshold amount. 
     
     
       12. The method of  claim 10 , wherein the one or more wireless input signals specify a heating mode command when a temperature sensed by the thermostat is lower than a temperature set point by a threshold amount. 
     
     
       13. The method of  claim 10 , wherein the one or more wireless input signals from the thermostat also specifies a temperature set point, and wherein the HVAC unit is run so as to condition the air in the inside space in the set mode toward the temperature set point. 
     
     
       14. The method of  claim 13 , wherein the HVAC unit is run in the set mode until the temperature set point is satisfied. 
     
     
       15. The method of  claim 10 , further comprising:
 receiving one or more subsequent wireless input signals from the thermostat to again activate the HVAC unit, wherein the one or more subsequent wireless input signals can specify either a cooling mode command or a heating mode command; 
 if a cooling mode command is received via the one or more subsequent wireless input signals, forcing the HVAC unit into the cooling mode; 
 if a heating mode command is received via the one or more subsequent wireless input signals, forcing the HVAC unit into the heating mode; and 
 with the mode of the HVAC unit set in response to the one or more subsequent wireless input signals, running the HVAC unit so as to condition the air in the inside space in the set mode. 
 
     
     
       16. A method for controlling an HVAC unit via a wireless thermostat that is located remotely from the HVAC unit, the HVAC unit having a cooling mode and a heating mode for conditioning air in the inside space, the HVAC unit having an onboard controller that is configured to determine whether the HVAC unit is in the cooling mode or heating mode in accordance with a control setpoint and an indication of local temperature, and whether the HVAC unit is activated or not, the onboard controller of the HVAC unit is configured to accept input signals wirelessly transmitted from the remotely located thermostat, the method comprising:
 the remotely located thermostat comparing a sensed temperature in the inside space with a set point, and determining if the sensed temperature is different from the set point by at least a predetermined amount; and 
 if the sensed temperature is different from the set point by at least the predetermined amount, the thermostat wirelessly sending one or more input signals to the onboard controller of the HVAC unit, wherein the one or more input signals specifies either a cooling mode command or a heating mode command, the one or more input signals causing the onboard controller of the HVAC unit to override a mode determined by the onboard controller and instead to set the HVAC unit to either the cooling mode or the heating mode in accordance with the sent command, and the one or more input signals also setting the control setpoint of the onboard controller to a value that will cause the onboard controller to activate the HVAC unit in the particular one of the cooling mode and the heating mode. 
 
     
     
       17. The method of  claim 16 , wherein the HVAC unit is run in the particular one of the cooling mode and the heating mode until the set point is satisfied. 
     
     
       18. The method of  claim 16 , wherein if the sensed temperature is lower than the set point by at least the predetermined amount, the one or more input signals specifies a heating mode command. 
     
     
       19. The method of  claim 16 , wherein if the sensed temperature is higher than the set point by at least the predetermined amount, the one or more input signals specifies a cooling mode command. 
     
     
       20. The method of  claim 16 , wherein:
 if the sensed temperature is lower than the set point by at least the predetermined amount, the one or more input signals specifies a heating mode command; and 
 if the sensed temperature is higher than the set point by at least the predetermined amount, the one or more input signals specifies a cooling mode command.